Evolutionary history of the sequestrate genus Rossbeevera (Boletaceae) reveals a new genus Turmalinea and highlights the utility of ITS minisatellite-like insertions for molecular identification.
Evolutionary history of the sequestrate genus Rossbeevera (Boletaceae) reveals a new genus Turmalinea and highlights the utility of ITS minisatellite-like insertions for molecular identification.
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DOI：
10.3767/003158516x691212
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发表时间：
2016-12
期刊：
影响因子：
9.1
通讯作者：
Maekawa N
中科院分区：
文献类型：
--
作者：
Orihara T;Lebel T;Ge ZW;Smith ME;Maekawa N
隔离（松露状）担子菌属 Rossbeevera、Chamonixia 和 Octaviania 与表层蘑菇属 Leccinum 和 Leccinellum 密切相关。为了阐明该群体中几个未描述的隔离类群的特性和位置，并揭示 Rossbeevera 及其同类的进化历史，我们基于三个核（ITS、nLSU、EF-1α）和两个线粒体 DNA 位点（ATP6 和 mtSSU）以及精确的形态学观察进行了系统发育分析。对三个核位点的系统发育分析表明，存在着复杂的进化历史，多个分支中存在隔离子实体，其中包括先前未被识别的罗斯比维拉姐妹分支。在这里，我们提出了一个新的隔离属，Turmalinea，有四个新种和一个新亚种，以及两个新的 Rossbeevera 种。三基因座核系统发育解决了Rossbeevera-Turmalinea谱系内的物种水平分歧，而基于两个线粒体基因的单独系统发育对应于每个物种水平谱系内的地理距离，并表明Rossbeevera的几个种内谱系内存在不完全谱系排序（ILS）和基因渗入。此外，三个核单基因座系统发育之间的拓扑不一致表明，Rossbeevera 内的古代物种形成可能涉及相当大的 ILS。我们还在所有 Rossbeevera 和 Turmalinea 物种的 ITS2 内发现了异常长的、类似小卫星的插入。条形码间隙分析表明，与 ITS 区域的其余部分相比，该插入对于各个分类水平的区分提供了更多信息，因此可以作为这些属的独特分子条形码。
The sequestrate (truffle-like) basidiomycete genera Rossbeevera, Chamonixia, and Octaviania are closely related to the epigeous mushroom genera Leccinum and Leccinellum. In order to elucidate the properties and placement of several undescribed sequestrate taxa in the group and to reveal the evolutionary history of Rossbeevera and its allies, we conducted phylogenetic analyses based on three nuclear (ITS, nLSU, EF-1α) and two mitochondrial DNA loci (ATP6 and mtSSU) as well as precise morphological observations. Phylogenetic analyses of three nuclear loci suggest a complex evolutionary history with sequestrate fruiting bodies present in several clades, including a previously unrecognized sister clade to Rossbeevera. Here we propose a new sequestrate genus, Turmalinea, with four new species and one new subspecies as well as two new species of Rossbeevera. The three-locus nuclear phylogeny resolves species-level divergence within the Rossbeevera-Turmalinea lineage, whereas a separate phylogeny based on two mitochondrial genes corresponds to geographic distance within each species-level lineage and suggests incomplete lineage sorting (ILS) and gene introgression within several intraspecific lineages of Rossbeevera. Furthermore, topological incongruence among the three nuclear single-locus phylogenies suggests that ancient speciation within Rossbeevera probably involved considerable ILS. We also found an unusually long, minisatellite-like insertion within the ITS2 in all Rossbeevera and Turmalinea species. A barcode gap analysis demonstrates that the insertion is more informative for discrimination at various taxonomic levels than the rest of the ITS region and could therefore serve as a unique molecular barcode for these genera.